Lipo Experiences

[markwilliamson2001]

Hey guys..

I ran first time with Lipo on Friday, and it was interesting to say the least.
Good points:

Charged up packs (2) on wednesday evening from packet. Took about 25 minutes till they reached 8.40 volts and then pulled them off. Fitted to car, ran without problems, then after 1 race, topped up on charger with balancer.

No assembling, no battery bars or connectors to solder up.
I used the Trakpower 3200 pack which easily lasted 1 race (could maybe have done 2 races on 1 pack). Indoors with a 7.5L, the car was a handful (too much power, would have been okay in a 4wd I expect). Motor, battery and speedo came off cool after race, so all good! Could have got away with a 13.5 brushless I reckon on the tight indoor track with the Lipo Pack. biggest difference noticed was the lack of weight which affected jumping, and high speed balance of the car. I had to add 40g of weight to the front of the car around the servo to balance it up. The car definatly felt more stable with my older GP3300 NIMH's in, but I will try and add more weight to the car to make it more stable soon (fit a slim lead sheet under the lipo pack) and bring it closer to the weight of NIMH cells. I hope in my 4wd car the difference will not be as noticable.

Bad points (my fault really):
I was using 3rd party corally connectors which were a looser fit in the battery than I would have liked. If I rolled the car they came out very easily. I tried an older 'proper' corally on an old piece of wire and it was much more secure. Had to tape in connectors which was a bit unsightly, but worked. Just to change speedo to battery connectors now.

Roll on Lipo!

Mark

[frogger]

Welcome to the revolution I don't even own any other kind of battery for all of my cars which include Micro-T, 3 x Blaze's, B4, B44 and soon to be brushless RC8.

[jimmy]

I've had problems with poor quality corallys - missed my first regional win because of them they heated up because of the poor connection (brand new too!) and desoldered.

You can read my experiences with Lipo in the trakpower review on here - pretty similar really. In the touring car it was a DREAM - really no messing about, recharge after racing and that's it.. loads of power, like the very best team cells + a bit more!

First time in the buggy I found it a handful tbh - but I hadn't adapted my setup - slower motor / lead weights. Since then I've raced the Tamiya Durga with an entire strip of lead next to the trakpower and the car has been awesome and no different to drive from nimh cells, apart from feeling like I had some awesome cells in the car. Come off racing, bang it on charge & back out to marshall.

The only problem I've had was when I left the trakpower in vickys car for two weeks. The large capacitor on the Novak ESC totally drained and ruined the pack - my fault but it just shows you need to take care.

[mark christopher]

mark at worksop the top drivers were ading very little weight, and were adjusting shock/springs to suit the lighter car think niel cragg just added some ontop of his servo

[RogerM]

Well I tried lipo for the first time on saturday on my secreet test track (ok an old BMX course) and really didn't like them!

For me they have far too much punch (I am dropping winds at a pace though and will probably have to go back to brushed, as nobody seems to do 8.5 or 9.5 brushless motors which are on the BRCA list!!!).

I tried them in the car (RB5) with no weight and it ruined the handling ..... now at least I know that the extra weight I've added to the front even when running NiMhs was the right thing to do. I put a piece of stainless steel under the pack which actually brought the weight up to about 5g more than my E-Power 4500s and the handling was back to normal.

Was very interesting and I can see why those people who like loads of punch are raving about them but they are not for me as they are at the moment for sure!

As an aside has anybody run lipo with brushed motors? If so how so the motors hold up??

[mark christopher]

did you try altering your speedo profile? or even radio expo?

[RogerM]

Can't get lower than setting 1 (normally use 2 in the 2wd on NiMh)... LOL

To be fair I am struggling with the voltage from modern NiMh cells when used with brushless as I said, Lipo is just a step too far for me!!!

When I was racing 1/10th before I always ran 3 to 4 winds milder than everybody else anyway (i.e. if people where using 9s I'd be on 13s etc.) I just prfer a softer feel to the throttle.


Not saying Lipo won't suit a lot of people, just that for people like myself who like the throttle really mild might not be able to find what they are looking for.

[markwilliamson2001]

I kind of agree with RogerM here... I really found the car just too fast on Friday, on the indoor track. This was with no weight added to my B4 until the final when I added 40g to the front, which did improve things, but it still wasn't quite like racing before. I think it maybe easier for most 'clubbies' to just add weight to the car to bring it back up to what it was like with NIMH's as it then won't affect the handling, and just have the benefit of charging and maintenance of LIPO (which is what I was going for, rather than the weight benefit). It might be more interesting in my 4wd once I get that going.

[Cockerill]

Originally Posted by RogerM

For me they have far too much punch (I am dropping winds at a pace though and will probably have to go back to brushed, as nobody seems to do 8.5 or 9.5 brushless motors which are on the BRCA list!!!).

LRP/Nosram both have 8.5t motors on the list, Novak/Nosram also have 10.5T (altho this is a separate list). So there is only 9.5 missing, but with a range of sintered/bonded rotor's I'm sure you could get the feel you like.

[ianplimmer]

you could try dialing some negative exponential on the throttle to smooth it out, maybe 10-15 neg would be less aggresive

[Chrislong]

Hi guys. Running them and adapting the car to feel like before is what most will do, but I think that to keep the power (to a point) and adapt the setup with a light car will be ultimately quicker than a NIMH car.

Only time will tell.

What I do feel, is it is certainly worth having them even if there may be some work in finding a 3 way balance between driveability vs power vs weight.

I would usually run a 5.5L in my 2wd, and when i went to Lipo I put the 7.5R in and the car was still quicker than id like it to be but driveable and lively. I actually tried it with 5.5L and Lipo and the car was beyond mental, it was just completely howling insane, and me being so sensible, had to use it all ofcause and .... well, I may aswell have been driving with boxing gloves on.. but it was ace.

[frogger]

I run a 125gr lead plate under my Maxamps 6000mah lipo in my B4 along with the usual weight behind the bulkhead and 15gr by the servo. All in all about 160gr that I add and the car feels fantastic. I run a Novak 6.5R at 80 throttle end point and a neutral throttle curve and it seems perfect. I had it on the track for 40mins the other day and it was till going strong on the same pack with no recharge. I had to leave cause I broke a front wishbone.

Roger - too much punch!? What you talking about!?

[markwilliamson2001]

Without the extra weight Carl, the car is a handful, as I found out to my detriment. I cannot believe that Chris Long dropped two brushless winds to get the same feel. Seems like a 10.5 might not be such a bad idea indoors then methinks!

Regards
Mark

[vader]

Did a very clever man not once say 'light is right'? Surely a lighter car will be quicker with the correct setup

[markwilliamson2001]

Originally Posted by vader

Did a very clever man not once say 'light is right'? Surely a lighter car will be quicker with the correct setup

With on-road I would agree with you. off-road a lighter car will be less stable through bumps. I also think that we have got so use to driving the heavy cars, it is hard to go to a lighter car.

With enough setup changes, a lighter car maybe better, but we like the setup we have at the moment.

[Lowie]

I run Lipo too, for some months now and i luv it too.
Indeed, the Lipo's give more bite to the motor, but you get used to it ... and it has made me sometimes using a lesser performant motor inslippery conditions, then I should have done with a NiMh-pack.

Strange thing dough, I have two Trakpower 4900 Lipo's.
I ALWAYS charge them with the Trakpower balancer (just because the corally-pins of the balancer are easier to connect to the pack then the crocodile clips on my charger) ... and I treat them right, as I should. I have a Lipo Saver installed ...

But when I charge my two Trakpowers (4900) I can only add a maximum of around 3200mAh.
Now one thing I didn't know: It seems its better to charge slowly the first times. I always charged them at 4.9A (the Trakpower manual said I could charge at 5A , I just wanted to stick with 1C).

What did I do wrong? Is this usual with Trakpower Lipo's? how come I "lost" around 1700 mAH?
I guess I had about max 60 charges on every pack.

[Chrislong]

Originally Posted by markwilliamson2001

I cannot believe that Chris Long dropped two brushless winds to get the same feel.

Don't believe it, because that isn't what I said

i said I ran 5.5L with Nimhs, then went to 7.5R and Lipo = the car was slightly quicker..... But why should I type that again as you won't read it.

[frogger]

A lot can be done by throttle EPA, throttle curve, throttle punch, etc. tp get the same feel on a lot of combinations of batteries and motors. Lighter most certainly isn't always better but we've had those kind of discussions on here a lot already so won't go there again

[mark christopher]

Originally Posted by Lowie

I run Lipo too, for some months now and i luv it too.
Indeed, the Lipo's give more bite to the motor, but you get used to it ... and it has made me sometimes using a lesser performant motor inslippery conditions, then I should have done with a NiMh-pack.

Strange thing dough, I have two Trakpower 4900 Lipo's.
I ALWAYS charge them with the Trakpower balancer (just because the corally-pins of the balancer are easier to connect to the pack then the crocodile clips on my charger) ... and I treat them right, as I should. I have a Lipo Saver installed ...

But when I charge my two Trakpowers (4900) I can only add a maximum of around 3200mAh.
Now one thing I didn't know: It seems its better to charge slowly the first times. I always charged them at 4.9A (the Trakpower manual said I could charge at 5A , I just wanted to stick with 1C).

What did I do wrong? Is this usual with Trakpower Lipo's? how come I "lost" around 1700 mAH?
I guess I had about max 60 charges on every pack.

how are you measuring this?
to check a lipo's capacity you need to discharge to 6 volts (3 volts per cell) on a discharger (not cut out in the car) then recharge to max capacity
what charger do you have?

[RogerM]

Originally Posted by Cockerill

LRP/Nosram both have 8.5t motors on the list, Novak/Nosram also have 10.5T (altho this is a separate list). So there is only 9.5 missing, but with a range of sintered/bonded rotor's I'm sure you could get the feel you like.

I have since found that out, I'd been told that the 8.5 motors had been dropped.

Looks like it's good bye to all my Novak motors and to the Nosram / LRP range!


As for expo on the Tx anything over about -30% and the throttle curve is feels quite un-natural to me, hard to judge especially when backing off to a set point. I normally run -25% on brushed motors!

As for Carl's comment about too much punch .... you can only put so much power down through the tires and any more is wasted. As I spent over 10 years racing stock before ever going near a modified I've not got the most delicate touch ..... something that rallycross certainly hasn't helped!!!


Anyway, all that is way off topic .....

As I said I can see why lipo is popular amongst some drivers but feel it definately won't be for everybody.